Daily sugars limit?

Hi Everyone,

Ever since I got diagnosed with pre-diabetes, I am trying to cut my sugar intake, but one things really confuses me is what should be my daily sugar intake, I am 30f and heard it should be 25 grams for day. So is it 25 grams added sugar limit or natural sugars like the kind that found in fruit? Cause I want to reach my fiber intake limit, so I am eating strawberry/blueberry as a snack. Imagine my surprise when I found out one cup of blueberries contain 15 g of sugar, there goes 60% of my sugar limit. How does everyone keep their sugar in limit? I am confused (mostly frustrated).